In terms of area size, the 3rd largest country in the world is China. In terms of population, the third largest country is the United States. china The world's third large…st country is the United States of America in both land mass and population, being 9,629,091 sq km in size, containing 310,681,000 people and making up 4.52% of the world's population. By population and area, the US. By total area, the United States is the 3rd largest country in the world with an area of 9,826,675 km2.

The country with the third largest area is the United States of America. The U.S. has an area of 9 629 091 km2 or 3 717 813 sq mi. The United States ranks behind Russia and Ca…nada as the 1st and 2nd largest countries, and is closely followed by China in 4th.

Oceania is the smallest continent on the planet. The vast majority of the continent is made up of the Pacific islands. However, some of these islands have a considerable size.… Oceania's largest country is Australia, with an area of 7,686,850 km2 (4,776,387 sq mi). The second largest is Papua New Guinea, measuring 462,840 km2 (287,595 sq mi) in area. The third largest country, and answer to the question, is New Zealand. New Zealand has an area of 268,680 km2 (166,950 sq mi), and is also the third most populous country of Oceania, Australia and Papua New Guinea ranking first and second yet again.